Alles Door Oefening Den Haag (commonly known by the abbreviated name ADO Den Haag) is a Dutch association football club from the city of The Hague.

The club was for a time known as FC Den Haag, with ADO representing the amateur branch of the club. Despite being from one of the traditional three large Dutch cities, it has not been able to match AFC Ajax, Feyenoord or PSV in terms of success in the Eredivisie or in European competition. There is nonetheless a big rivalry with Ajax and Feyenoord. The words Alles Door Oefenen translate into Everything Through Practice in Dutch.